Backmasking (also known as backward masking) is a recording technique in which a sound or message is recorded backward onto a track that is meant to be played forward. Backmasking is a deliberate process, whereas a message found through phonetic reversal may be unintentional.

Backmasking was popularized by The Beatles, who used backward vocals and instrumentation in recording their 1966 album Revolver. Artists have since used backmasking for artistic, comedic, and satiric effect, on both analog and digital recordings. The technique has also been used to censor words or phrases for "clean" releases of songs.

Backmasking has been a controversial topic in the United States since the 1980s, when allegations from Christian groups of its use for Satanic purposes were made against prominent rock musicians, leading to record-burning protests and proposed anti-backmasking legislation by state and federal governments. Whether backmasking can be used subliminally to affect listeners is in debate by both sides.

﻿When discussing subliminal perception, many also bring up backmasking, recording a message within a song backwards. Jeff Milner has developed a collection of 14 popular songs which reportedly have hidden backward messages. The song clips can be played from the site forward, backward and include the lyrics. Jeff's backmasking site can be found at http://jeffmilner.com/backmasking/﻿

Backmasking is the process of reversing an audio signal and placing it in something meant to be played forwards. When played normally the message will sound like gibberish, however, when the song is played in reverse the original message can be heard. Some of the first instances of reversed audio were the result of The Beatles’ experimentation during the recording of Revolver. Since then, backmasked messages have turned up in all kinds of music with messages ranging from humorous to satanic. Today, reversing audio is a popular way to censor explicit words for radio. Here is a list of 10 famous instances of backmasking.